System of protecting riparian lands from overflow



n stence of large tide water reservoirs, such as` llnirnn ratas Paramlrica,

LINUS WV. BROWN, OF NEW ORLEANS, LOUISIANA.

SYSTEM OF PROTECTING RIPARIAN LANDS FROM OVERFLOW.

SPECIFICATION forming part of Letters Patent No, 488,422, dated December20, 1892.

Application led August 15,1892. Serial No. 4431077- (NO 111011610 To @ZZwhom t may concern:

Be it known that I, LINUS WV. BROWN, a citi-` zen of the United States,residing at New Orleans, in the parish of Orleans and State ofLouisiana, have invented certain new and useful Improvements in Systemsof Protecting Riparian Lands from Overiiow; and I do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appert-ains tomake and use the same. y

My invention relates to improvements in methods for protecting low-lyinglands from the disastrous overflow of rivers and other streams.

This invention is especially adapted to rivers having a considerabledifference of level between high and low water, and where the banks areprotected from overflow by artificial means, such as levees; and wherenatura-l` or artificial reservoirs for drawing off the wafter eitheralready exist, or may be conven-` iently created.

My invention is primarily designed for relieving the lower portions ofthe Mississippi river from disastrous overflow, the level of the landthere, being considerably lower than that of the river at high water,andthe eX- Lake Borgne, and Lake Maurepas, in `close proximity to thestream, renderingit possible to construct such works as are hereinafterdescribed within the limits of reasonable ex pense.

The drawings are illustrative of the conditions that prevail in theregion of the lower Mississippi, but while designed as especiallyapplicable to the Mississippi river, my invention may be employedwherever suitable conditions exist by nature, or may be created by man.

Reference is had to the accompanying drawings, in which the same wordsof reference refer to similar parts throughout the several views.

Figure l represents a plan View of a river iiowing in the direction ofthe arrow l; alake, sea, or other reservoir, not far distant from thesaid river; anda channelor tail race connectng the two; the saidtailrace being bounded by side walls or levees to prevent the lateraliiow of water, and being provided at its end next the river with anon-erosive Weir or dam, of a height slightly less than that of theadjoining levees, which normally keep the river Within its bounds. Fig.2 represents an enlarged section of Fig. l along lthe line i12-x, andlooking in the direction of the arrow 3; and Fig. 3 represents anenlarged section of Fig. l, along the line g/-g/, and looking in thedirection of the arrow It.

In the Mississippi river, in recent years, it has been found that themaximum height has been increasing relative to the height of theadjacent lands. Vhether this be due to growing obstructions at itsmouth, or to the more rapid drainage of its basin is immaterial as topresent purposes; but this increased height of the water can apparentlybe met in only two ways. First, by steadilyincreasing the height of thelevees, already dangerously high; and, second, by furnishing some meansfor carrying off the superiiuous water.

My invention consists in providing overflow conduits, adapted to carryoff the upper layers of water when 'the height exceeds a certainpredetermined point. For this purpose I propose to employ artificialchannels bounded by side levees to prevent the lateral iiow of thewater, connecting the river with some reservoir of large area,preferably one connected directly to the sea. In order that the naturalchannel of the river may not be disturbed under normal conditions, Ipropose a Weir or dam preferably faced with brickwork or masonry, andconstructed as in Fig. 3, to resist the erosive effect of the water.vWhen the water in the river rises higherthan the top of this Weir itwill flow over, and find its way back between the side levees of thereservoir, as shown in Fig. l. Should the level of the river bematerially higher than the height of the weir, the water above the weir,and flowing back through the tail race, will be of considerable depth,and will have considerable velocity. Now by having this Weir ofsufficient length, the artificial passageway for the Water will besuiicient to carry off .a large proportion of the'total amount of waterflowing down the river when it is very high, and will thus preventtheriver from rising beyond the height of the Weir, which I shall call thedanger line, for all points below the Weir. By having the Weir facedwith non-erosive material such as masonry, mattresses of willows, orother equivalent devices, the height of theweir will not be materiallychanged by erosion, while the overiiowing water will cut one or morechannelsin the tail raee,allowinga ready flow back, and preventing undueerosion on the side levees. The said side levees may be facined orotherwiselprotected against erosion, wherever it is found necessary.When practicable, the weir should be preferably constructed in the bendof the river, where the impinging current flows in the direction of theaxis of the tail race, as shown in Fig. 1, where the arrows I and 2indicate the direction of the current in the river and the tail racerespectively. It will not be found necessary to build the side levees ofthe tail race as high near the reservoir as they are near the river.

I am aware that various systems of relieving the Mississippi by means ofoutlets, have been proposed; but in all of such systems there has beenno effort or intention to limit the flow of the water through the outletto a given height of the river,but on the contrary, it has been proposedto allow the said outlet to cut an enlarging channel for itself. Theresult of the deepening and enlargening of this channel, would be aslacking up of the water in the portions of the river proper below saidchannel, causing a deposit of sedimentary matter, the formation of sandbars, and injury to the navigation of the stream, but by limiting theoverflow to such times only as the river is dangerously high, therequisite amount of protection is obtained, and at the same time injuryto the navigable channel of the river is obviated.

It will be obvious that if it be impracticable to carry off a sufficientamount of water with one long Weir, the number of the said weirs may beincreased indefinitely, until the conjoint carrying capacity of thevarious outlets may equal that desired. Moreover, by having one weirconstructed in a series of non-erosive steps from end to end, a gradedquantity of water may be carried oif at any and all stages of highwater.

Having thus described my invention, what I claim, and desire to secureby Letters Patent of the United States, is:-

1. A means of preventing disastrous overflow to low-lying riparian landsprotected by levees, which consists in a portion of said levee lowered,at a bendin the river, and said lowered portion being protected againsterosion, and an overflow channel in rear of said lowered portion,openinginto a reservoir of sufficient capacity, substantially as and forthe purposes described.

2. The hereinbefore described means for preventing disastrous overflowto low-lying riparian lands protected by levees which consists of anon-erosive weir forming a portion of the line of levees and arrangedwith its top at a predetermined distance below the tops of said levees,a channel back of said weir, means for confining the water in saidchannel, and a reservoir of sufficient capacity in rear of said channel,substantially as and for the purposes described.

3. The herein-described means for preventing disastrous overflow tolow-lying riparian lands protected by levees, which consists of a Weirforming a portion of the line of levees and arranged with its top at apredetermined distance below the tops of said levees, the said weir andits approaches being protected from erosion by a masonry facing; achannel back of said weir, banks for confining the water in saidchannel, and a reservoir of sufficient capacity in rear of said channel,substantially as and for the purposes described.

4. The hereindescribed means for preventing disastrous overflow tolow-lying riparian lands protected by levees, which consists of a weirforming a portion of the line of levees and arranged with its top at apredetermined distance above low water mark, the said weir and itsapproaches being protected from erosion by a non-erosive apron slopingto the front and rear; a channel back of said weir; banks for confiningthe water in said channel, and a reservoir of sufficient capacity inrear of said channel, substantially as and for the purposes described.

In testimony whereof I affix my signature in presence of two witnesses.

LINUS W. BROWN.

Vitnesses:

FELIX J. DREYFoUs, GEO. MONTGOMERY.

